Surgical method, kit of parts, and implant

ABSTRACT

A surgical method is provided, the method including the steps of: providing an artificial or allograft flexible planar structure; providing an implant, the implant including material liquefiable by mechanical oscillation, exposing a surface region of hard tissue or hard tissue substitute material; positioning the implant on an exposed area of the hard tissue or hard tissue substitute material; and fastening the implant to the hard tissue or hard tissue substitute material by impinging the proximal end of the implant with mechanical oscillation and simultaneously pressing the implant against the hard tissue or hard tissue substitute material while the distal end of the implant protrudes into a cavity of the hard tissue or hard tissue substitute material and regions of the liquefiable material are in contact with the hard tissue or hard tissue substitute material, and thereby liquefying at least a portion of the liquefiable material, and letting the liquefiable material resolidify.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention lies in the field of medical technology and relates to amethod of fixing an object within the human or animal body by means of aflexible planar structure, for example a web. It further relates to akit of parts for carrying out said method and to an implant.

2. Description of Related Art

It has been known to use artificial membranes in surgery for coveringsoft tissue, for example in the case of a hernia, such as an inguinalhernia. Examples of such membranes are fabrics. For many applications itwould be desirable, however, to extend the possibilities of existingsurgical methods and of devices used therefor.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a surgical method whichintroduces new possibilities of fixing tissue parts or artificialobjects within a human or animal body, of correcting the position oftissue parts or artificial objects, or of applying forces to tissueparts or artificial objects.

According to an aspect of the invention, a surgical method is provided,the method comprising the steps of:

-   -   Providing an artificial or allograft or autograft flexible        planar structure;    -   Providing an implant, said implant comprising a proximal end and        a distal end and further comprising a surface region of material        liquefiable by mechanical movement, or further comprising a        hollow space that is at least partially filled by material        liquefiable by mechanical movement and at least one channel        (preferably a plurality of channels) between the hollow space        and an implant surface, so that the liquefiable material may        reach a surface region when a mechanical movement is applied to        the liquefiable material;    -   Exposing a surface region of hard tissue or hard tissue        substitute material;    -   Positioning the implant on an exposed area of the hard tissue or        hard tissue substitute material; and    -   Fastening the implant to the hard tissue or hard tissue        substitute material by:        -   Impinging the proximal end of the implant with mechanical            movement and simultaneously pressing the implant against the            hard tissue or hard tissue substitute material while the            distal end of the implant protrudes into a cavity of the            hard tissue or hard tissue substitute material and regions            of the liquefiable material are in contact with the hard            tissue or hard tissue substitute material, and thereby            liquefying at least a portion of the liquefiable material;            and        -   letting the liquefiable material resolidify;    -   wherein the flexible planar structure is fastened to the        implant, either before impinging the implant by mechanical        movement or while impinging the implant by mechanical movement        or after impinging the implant by mechanical movement.

Flexible in the context of this text means “offering essentially noresistance against bending”, i.e. having no flexural rigidity or onlyhaving a small flexural rigidity. Especially, the flexible planarstructure is not resilient in the sense of being capable of excerpting aspring force.

The hard tissue or hard tissue substitute material may be a bone tissue,such as a live bone tissue. Indeed, the advantages of the approachaccording to the invention are most evident for applications in respectto live bone tissue, since for such applications it is often importantthat the implantation is quick and provides a high primary stability.The hard tissue or hard tissue substitute material, however, as analternative, may not be live bone tissue or bone substitute material(such as bone cement) or another hard tissue, such as dentin or possiblycartilage, or their substitute material. In the following discussion,the hard tissue or hard tissue substitute material is primarilymentioned as bone tissue; however, the teaching also applies to theother kinds of hard tissue or hard tissue substitute material.

The method may be carried out in situ with live bone tissue. As analternative, it may also be carried out ex situ.

The mechanical movement is preferably a mechanical oscillation,especially ultrasonic vibration. It may, in certain special cases, alsobe an unidirectional movement such as a rotational movement.

The invention thus proposes to fasten a web (or other flexible planarstructure) to a bone tissue (or other hard tissue or to hard tissuesubstitute material) in order to influence the position of tissue partsor artificial implants and/or to apply forces thereto. Especially, theinvention proposes to do so by means of a method providing a connectionthat is permanent and tight but nevertheless allows for some remainingresilience. For example, the web may be fastened by means of a pluralityof comparably small implants so as to distribute potential forces uponthe web on a large area.

The flexible planar structure can be any kind of web (in the broadestsense of the word), for example any membrane or foil or fabric. Examplesof such webs include artificial fabrics such as webs of plasticmaterial, of metal fibers, of other fibers, and hybrid artificialfabrics. Such webs may be nonwovings, weavings, knittings, breadings,embroidered textiles or other fabrics. The advantages and disadvantagesof different textile structures for medical applications are, forexample, discussed in the publicly available PhD Thesis for the SwissFederal Institute of Technology Zurich by Ziya Erdal Karamuk“Embroidered Textiles for Medical Applications: New Design Criteria withRespect to Structural Biocompatibility”.

Further examples of webs include foils or membranes, such as polymerfilms or also porous films e.g. made of materials e.g. expandedtetrafluorpolyethylene (ePTFE), commercially available as membranes fromGore & Associates.

As yet another alternative, the flexible planar structure can also be anatural tissue structure such as an allograft tendon or ligament, anallograft dura, chondral tissue or decalcified primarily collagenoussheet like material.

Whereas the flexible planar structure can have any shape, usually theextension in one dimension (thickness) is clearly smaller than theextension in the other dimensions (length, width). For example, thethickness may be smaller than the smaller of the length and the width byat least a factor of 5, preferably at least a factor of 10, usually byat least a factor of 20 or more. The flexible planar structure may havea lengthy shape (ratio between length and width greater than 10), butthe invention is also especially suited for flexible planar structureswhere the ratio of the length and the width is smaller than 10.

There are two alternative ways of producing the bone tissue cavity. As afirst option, the cavity of the bone tissue may be pre-fabricated bymaking (for example by drilling) a bore in the bone tissue, wherein thewidth and depth of the hole are at most as large as the width and lengthof the portion of the implant that will finally protrude into thecavity. The implant may then be of any suitable material composition,provided its surface has the necessary portions of liquefiable materialor may be provided, from the inside through channels (openings) withsuch liquefiable material. It may for example be a hybrid with a core ofa first plastic material, of a metal or of a ceramic or reinforcedplastic and a cladding of thermoplastic material. Alternatively, theimplant may also be completely made of the thermoplastic material. Asyet another alternative, the implant may comprise a hard shell, not ofthermoplastic material, with a filling of thermoplastic or thixotropematerial and openings in the shell through which the thermoplastic orthixotrope material exits during implantation.

As a second option, the cavity may be produced by the introduction ofthe implant into the bone tissue by means of mechanical oscillations(preferably ultrasonic vibrations). Before this, the Periosteum may beremoved at the appropriate location. The implant then preferablycomprises a hard core of a metal, e.g. of titanium, of a titanium alloy,or of another suitable metallic or ceramic material such as zirconia, apossibly reinforced plastic material, another material or a combinationof at least two of these. The implant may also comprise a cutting edgefor cutting into the bone tissue and/or a pronounced tip to be driveninto the bone tissue. The cutting edges cutting into the bone tissueduring implantation may also contribute to the anchoring of the implant.Means especially adapted for driving the implant into bone tissue, suchas self-reaming structures, are for example described in WO 2005/079696.

Further teachings and alternative versions of implants may, for example,be found in WO 02/069 817, WO 2004/017 857, or WO 2005/079 696, theteachings of all of which are incorporated herein by reference.

The liquefiable material preferably is provided at a surface portion ofthe implant. In this case, the liquefiable material is preferablythermoplastic.

As an alternative, the liquefiable material may be arranged in a hollowspace of the implant. Then, it forms the surface region of liquefiablematerial on the implant that can be brought into contact with the bonetissue and can be excited by mechanical oscillation only after it hasbeen excited and/or pressed out through channels (openings) onto thesurface. In the case of the liquefiable material being positioned in ahollow space of the implant, the mechanical vibration is advantageouslynot applied to the implant until the implant is positioned in the cavityand then only to the liquefiable material. In this case, the liquefiablematerial may be a thermoplastic material or a thixotropic, particulate,hydraulic or polymeric cement, as also used in orthopaedics foranchoring implants or e.g. for the infiltration of diseased collapsedvertebrae.

Simultaneously, with the insertion of the implant into the bone tissuecavity or with producing the cavity by introducing the implant,respectively, the implant is impinged with mechanical vibration. Thiscauses the liquefiable material, advantageously a thermoplasticmaterial, to liquefy at points of contact with the bone tissue. Sincethe bone tissue along the cavity wall comprises unevenness and/or poresand/or artificially made retention structures, for example threads orundercuts, the material liquefied by the oscillations penetrates thesestructures and is thus brought into intensive contact with the bonetissue surface. This is especially the case in the spongy bone tissuebut also in the cortical bone tissue. The cavity wall may in additioncomprise structures specifically fashioned for this purpose. Having set(solidified) again, the liquefiable material forms a link between theimplant and the bone tissue interlocking the two by positive fit andpossibly adhesive bond. The penetration of these structures by theliquefiable material thus results in an anchoring of the implant in thebone tissue by a kind of micro-interlocking. This effect and methods forimplanting, by mechanical oscillations implants in bone tissue andimplants therefor are described in mentioned WO 02/069 817, WO 2004/017857, and WO 2005/079 696, all incorporated herein by reference.

The implant according to the invention is thus stabilized in the cavityimmediately after the implantation by its connection with the bonetissue through the liquefiable material, wherein this stabilization iseffective against pressure and tension (e.g. parallel to an implantaxis) as well as, as the case may be, against torsional loading.

All named effects lend the implant, according to the invention, aprimary stability, which is in most cases sufficient to withstandloading immediately after implantation. The connective structures ofthermoplastic material possess a comparable or lesser elastic modulusthan the local recipient bone structure, e.g. the osseous trabeculus),and their ability to creep make them particularly advantageous forabsorbing shocks and for reducing excessive stress. Due to bodymovements, flexible structures tend to be subject to recurring forces.As a consequence, on the one hand, state-of-the-art non-flexibleconnections would bring about the danger that they start loosening aftersome time. Thus, adhesion to live tissue, by natural tissue growth, ofan object to be fixed is prevented. If a connection is made too tight,on the other hand, natural tissue growth has been proven to be slow andflawed. The method according to the invention, however, features thesubstantial advantage of providing a non-detachable connection by whichthe bone tissue and the implant are at a relative rest against eachother. Nevertheless, the liquefiable material's elasticity preventsshielding the bone-implant interface from those moderate stresses thatare known to stimulate osseointegration. Typical values for such stressinduced stimulative strains are between 0.05% to 0.5%. As a consequence,osseointegration by natural tissue growth of the implant to the bonetissue and/or of the flexible planar structure to the bone tissue isenhanced. At the same time, these connections prevent majordisplacements between implant and bone tissue and thus between the bonetissue and the flexible planar structure, which displacements would leadto the disruption of the osseointegration process.

Detachable connections may—and will—detach when subject to recurringforces for a long time. The method according to the invention, incontrast, allows the rigid structure of the body, namely the bones, tobe used for fixing or adjusting the position of a thin flexiblestructure in a force bearing manner and by a non-detachable, permanentconnection.

Forces tearing the flexible planar structure may be especially wellabsorbed if the connection is a large area connection. This may be doneby using a plurality of implants all implanted by the process inaccordance with the above description. Different implants may, accordingto a special embodiment, be connected to each other by bridge likestructures.

The connection between the implant(s) and the flexible planar structuremay be brought about in different ways:

A. Pre-fabricated connection: The implant(s) and the flexible planarstructure may be a one-piece element, i.e. they are manufactured fromone piece of material or are fastened to each other before operation (exsitu).B. Connection by macroscopic positive fit: The implants may, forexample, protrude through openings in the flexible planar structure andmay have a head-like bulge or a claw like structure preventing theflexible planar structure from loosening. The openings may bepre-fabricated, produced ex situ or in situ with an appropriate tool ormay be brought about by piercing by a tip of the implant itself.C. In accordance with a variant of option B, a bulge-like structure maybe manufactured only after both the implant(s) and the flexible planarstructure have been placed. The implant then functions as a kind ofrivet. Especially preferred are embodiments where the implant comprisesa tip-like structure towering towards the proximal side. The flexibleplanar structure may then, after the implant(s) have been set, bepre-tensioned and be lowered onto the bone with the protruding implants'tips. Thereafter the tips are deformed into the bulges. This may be doneby ultrasonic vibration, heating, mechanical deformation or acombination of these. This embodiment is especially suited for placingthe flexible planar structure under tension.D. In accordance with a variant of option B, a plurality of implants maybe connected by a bridge like element that prevents the flexible planarstructure from loosening.E. Connection by micro-interlocking: The flexible planar structure maybe porous and/or absorbent and/or comprise unevennesses, and the implantmay comprise liquefiable material in the region where it is in contactwith the flexible planar structure. Then, like for the bone tissue, theliquefiable material may penetrate these structures resulting in ananchoring of the implant in the flexible planar structure and thus in anintimate connection between the implant and the flexible planarstructure.F. Connection by welding: If the flexible planar structure isliquefiable and the implant comprises liquefiable portions in a regionin contact with the flexible planar structure, such material portionsmay fuse together to form an intimate connection.

“Porous” in this context includes a textile, for example meshed,structure where the spacings between the filaments act as open pores.

The different options may be combined with each other. Especially, it ispreferred to combine either of options B, C, and D with option E and/oroption F. A combination of option E and option F is achieved if thefabric includes (or even consists of) fibers that are thermoplastic andmay be liquefied under the conditions during implantation and/orfastening the flexible planar structure to the implant.

In the case of option E. (micro-interlocking of the flexible planarstructure with the implant(s)) and/or option F., the melting of theliquefiable material of the implant may be done in the same step withthe implantation. Then, the liquefiable material penetrating the bonetissue structures and the liquefiable material penetrating the flexibleplanar structure are melted in one step by applying ultrasonicvibrations to the implant by one tool. As an alternative, this may be atwo-step process, where for example first the liquefiable material incontact with the bone tissue is liquefied by applying oscillations witha first amplitude and frequency and then the liquefiable material incontact with the flexible planar structure is liquefied by applyingoscillations with a second amplitude and frequency and/or applied atsecond surface portions not identical surface portions to which thefirst oscillations are applied. Instead of or in addition to beingmelted by ultrasonic vibration, the proximal head of the implant mayalso be deformed by heat. Also, a combination with deformation bymechanical deformation.

The implant according to the invention may, according to a preferredembodiment, be inserted into the bone tissue cavity without substantialrotation (in particular without rotation greater than) 360°. It may beinserted substantially in the direction of an implant axis.

One of the achievements of the invention is that it makes a quickanchoring of the flexible planar structure in the hard tissue possible.This is since the procedure of fastening the implant to the hard tissueby having structures of the hard tissue be interpenetrated—as disclosedabove—by liquefied material that re-solidifies is quick and provides ahigh primary stability. Also, the step of fastening the flexible planarstructure and the implant to each other may be a quick step that mayinclude melting thermoplastic material in a zone of contact between theimplant and the flexible planar structure. Said thermoplastic materialmay stem from the implant, from the flexible planar structure or fromboth, and may cause a welding connection and/or may interpenetratepores, for example, of the flexible planar structure being a fabric.Finally, optionally the steps of fastening the implant to the hardtissue or tissue substitute material and of fastening the flexibleplanar structure to the implant may be combined in one single step and,for example, be done with a single tool.

The implant according to the invention may comprise a cylindricalportion or a portion tapered towards its distal end. It may furthercomprise energy concentrators, edges, and/or protrusions.

The liquefiable material to be applied in the implant according to theinvention may, depending on the application, be biologically resorbable.As an alternative, the material may be biologically compatible, i.e. ofbone-friendly and advantageously osseointegrative character. Alsosurface regions of the implant which are not liquefiable, but come intocontact with bone tissue may be biologically compatible. On thesesurface areas osseointegration of the implant can begin immediatelyafter implantation and can successively relieve the anchoring by theresorbable thermoplastic material. It is possible also to use anon-resorbable thermoplastic material in such a manner that itsanchoring in the bone tissue permanently complements or even replacesthe anchoring by osseointegration.

Biologically resorbable liquefiable materials suitable for theindividual implant according to the invention are: thermoplasticpolymers based on lactic and/or gluconic acid (PLA, PLLA, PGA, PLGA etc)or polyhydroxy alkanoates (PHA), polycaprolactones (PCL),polysaccharides, polydioxanones (PD), polyanhydrides, polypeptides,trimethyl-carbonates (TMC), or corresponding copolymers, or mixedpolymers, or composites containing said polymers. Suitablenon-resorbable thermoplastic materials are e.g. polyolefines (e.g.polyethylene), polyacrylates, polymethacrylates, polycarbonates,polyamides, polyesters, polyurethanes, polysulfones,liquid-crystal-polymers (LCPs), polyacetals, halogenated polymers, inparticular halogenated polyolefines, polyphenylene sulphones,polysulfones, polyethers, or corresponding copolymers and mixed polymersor composites containing said polymers. Composites included compositesgenerated by adding fillers (particulates, fibers, whiskers, . . . )from materials like calcium phosphates, phosphate based glasses(bioglasses), carbonates, sulfates, high atom number comprising elementsfor x-ray contrast. The materials may be provided with pharmacologicallyactive substances, e.g., antibiotic agents, stimulating agents (growthfactors), antiinflammatory agents, zytostatic agents, combinations ofthese, and/or precursors thereof.

Particularly suitable as resorbable liquefiable materials are:poly-LDL-lactide (e.g. available from Böhringer under the trade nameResomer LR708) or poly-DL-lactide (e.g. available from Böhringer underthe trade name Resomer R208); as non-resorbable liquefiable material:polyamide 11 or polyamide 12.

The flexible planar structure may serve for one or more of the followingpurposes:

It may be an artificial or allograft ligament or tendon.

It may be an artificial or allograft based dural tissue like material torepair soft tissue lesion e.g. of the dura or of the spinal cord.

It may serve as an none-adhesion layer to prevent tissue adhesions aftersurgical intervention e.g. to cover the vertebral access side afterinsertion of a interbody fusion device or intervertebral disc.

It may serve as an adhesion promotion membrane allowing or stimulatingtissue ingrowth.

It may serve for stabilizing or repairing skeletal structures such asthe vertebra or sub-structures thereof, e.g., the annulus fibrosus.

The flexible planar structure may be part of an implant, e.g. anextensional membrane to attach bone fragments or used to attach theimplant to a distinct osseous bonding site, such as a nucleus prosthesisformed as a textile bag filled with a gel, which is introduced into theintervertebral disk cavity after nucleotonomy and which swells therein.

The flexible planar structure may also be a part of a larger implant(distinct from the implants used to affix the flexible planar structureto the bone material), for example a shoulder prosthesis.

If the flexible planar structure is transparent, it may be used tocouple light into the (also transparent) implant, or the implant may beused to couple light into the flexible planar structure which, forexample, covers a tumor, wherein the light is used to stimulate a tumorantagonizing agent.

The flexible planar structure may be positioned and fixed so as to forma bag-like container holding some element or material, for examplemedication to be slowly resorbed, through the flexible planar structure,by the body.

The flexible planar structure may also be impregnated with an agent.

The flexible planar structure may serve as a spacer between elements ofa, for example, osteoarthritic joint—according applications to thetrapeziometacarpal (TMC) joint are, for example, known from the companySBI.

The flexible planar structure may release pharmacologically activesubstances e.g. to stimulate a healing process or a growth process byadded agents, by its composition and/or by its structure (porearchitecture).

The flexible planar structure may be used for positioning and holding inplace soft tissue and/or soft tissue substitute material within thebody. This includes the prevention and/or repair of a hernia such as ahernia of the intervertebral disc. An embroidered fabric for holding inplace of a intervertebral disc implant is, for example, commerciallyoffered by Nuvasive.

The flexible planar structure may be used to cover cavities in bone,e.g. after bone harvesting and to serve as bone guidance membrane.

The flexible planar structure may be used to cover soft tissue cavitiesand to guide soft tissue regeneration e.g. for cartilage regenerationbeing a periosteal flap or an allograft or an artificial membrane.

The flexible planar structure could also act as scaffold for tissueingrowth either in vivo or in-vitro by being pre-seeded and cultivatedwith suitable cells (e.g. stem cells, chondrocytes, osteoblasts,fibroblasts, cells related to the tendonous endplate) to further enhancethe repair and regenerative capacity of the construct.

The flexible planar structure may serve as vascular prosthesis.

The flexible planar structure may be used for embedding at least oneconductive coil for achieving, with the aid of the flexible planarstructure, local high resolution in an MRI image.

The flexible planar structure may embed nanomagnetic particles or otherresistance elements with the aid of which locally, by alternatingfields, hyperthermias may be caused and used for antagonizing a tumor.

The flexible planar structure may embed identification elements such asRFID tags.

Two or more of the above can be combined where such combination makessense.

According to an other aspect of the invention, a surgical method isprovided, the method comprising the steps of:

-   -   Providing an artificial or allograft flexible planar structure;    -   Providing a plurality of implants, each comprising a proximal        end and a distal end and further comprising a surface region of        material liquefiable by mechanical oscillation, or further        comprising a hollow space that is at least partially filled by        material liquefiable by mechanical oscillation and at least one        channel between the hollow space and an implant surface, so that        the liquefiable material may reach a surface region when a        mechanical oscillation is applied to the liquefiable material;    -   Exposing a surface region of live bone tissue;    -   Positioning the implants on an exposed area of the bone tissue        and positioning at least a section the flexible planar structure        on said exposed area, so that the implants reach through        openings in the flexible planar structure;    -   Impinging the proximal end of the implants with mechanical        oscillation and simultaneously pressing the implant against the        bone tissue while the distal ends of the implants protrude into        cavities of the bone tissue and regions of the liquefiable        material are in contact with the bone tissue, and thereby        liquefying at least a portion of the liquefiable material;    -   Liquefying, by mechanical vibration, liquefiable material of the        implants being in contact with the flexible planar structure and        thereby penetrating at least one of pores and of spaces of the        flexible planar structure by the liquefied liquefiable material;        and    -   letting the liquefiable material resolidify.

According to yet another aspect, the invention concerns a kit of partsfor performing a surgical operation, for example an operation accordingto any one of the features discussed in this text, the kit comprising:

-   -   an artificial or allograft flexible planar structure, and        further comprising    -   a plurality of implants, each comprising        -   a proximal end and a distal end,        -   a surface region of material liquefiable by mechanical            movement, or a hollow space that is at least partially            filled by material liquefiable by mechanical movement and at            least one channel between the hollow space and an implant            surface, so that the liquefiable material may reach a            surface region when a mechanical movement is applied to the            liquefiable material, and        -   a fastening means for fastening the implant to the flexible            planar structure before being implanted, while being            implanted, or after being implanted.

For example, the flexible planar structure may comprise a plurality ofpores into which liquefied material from the implant may interpenetrateso that an intimate connection may be formed. To this end, the implantmay comprise surface portions that are, when the flexible planarstructure and the implant are in their destined position, in contactwith the flexible planar structure. The flexible planar structure may,for example, be a fabric, where the pores are spaces between the fibers.In addition or as an alternative, the flexible planar structure may bethermoplastic. The flexible planar structure may, for example, befoil-like.

The fastening means of the implant may comprise the mentioned surfaceportions of thermoplastic material in contact with the flexible planarstructure. In addition, or as an alternative, the fastening means mayinclude a particular shape such as a proximal broadening, which servesfor fastening the flexible planar structure, for example like the headof a nail, like a hook, a bridge etc. In addition or as an alternative,the fastening means may be rivet-like, i.e. formed after the positioningof the implants and the flexible planar structure only. Further optionsare possible and described in the following description.

According to a special embodiment, the flexible planar structure may bea suturing fabric for serving as a base for suturing an element to thehard tissue.

An even further aspect of the invention concerns an implant comprising

-   -   a proximal end and a distal end,    -   a surface region of material liquefiable by mechanical movement,        or a hollow space that is at least partially filled by material        liquefiable by mechanical movement and at least one channel        between the hollow space and an implant surface, so that the        liquefiable material may reach a surface region when a        mechanical movement is applied to the liquefiable material, and    -   a fastening means for fastening the implant to the flexible        planar structure before being implanted, while being implanted,        or after being implanted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an implant and a flexible, planar structure attached to abone tissue in cross section;

FIG. 2 is a view of a flexible planar structure fastened to a bonetissue by means of a plurality of implants;

FIG. 3 shows an illustration of a further embodiment of an implantaccording to the invention;

FIGS. 4 a, 4 b, 5 a, 5 b show embodiments of an implant with a pluralityof micro-pins;

FIGS. 6 a, 6 b, 7 a, 7 b, 8 a, 8 b, illustrate embodiments of implantsor multi-implant elements with bridge-like or claw-like structures;

FIG. 9 shows a suturing base fastened by the method according to theinvention;

FIGS. 10-15 show applications of the method and device according to theinvention;

FIG. 16 shows a flowchart of the method according to the invention;

FIG. 17 discloses an embodiment where the implant is not pre-formed butformed in-situ; and

FIG. 18 discloses an embodiment where the connection between the implantand the flexible planar structure is achieved by applying a pullingforce onto the implant.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an implant 1 with a head 1.1 formed at a proximal end, acylindrical or tapering shaft 1.2, and a tip 1.3 at a distal end. Theimplant is introduced into a cavity formed in a bone tissue 2. Anartificial flexible planar structure, namely a fabric 4 lies on the bonetissue and is fastened thereto by means of the implant 1. The fabric 4may, for example, be a fabric of a kind as such known in surgery, forexample a mesh of knitted nonabsorbable polypropylene filaments, ofother plastic material filaments, of metal filaments (such as titaniumfilaments), or of any other tissue friendly or resorbable material. Thefabric comprises an aperture trough which is penetrated by the implant.The aperture may have been produced in that the fabric 4 was pierced bythe implant 1. As an alternative, the aperture may have beenpre-fabricated ex situ.

The implant is anchored in the bone tissue 2 in that it comprises asurface region 1.4 of thermoplastic material that has been liquefied bymechanical vibration and resolidified after penetrating structures ofthe adjacent bone tissue, as described above.

Optionally, the surface region that includes the liquefiable materialmay extend to the place where the implant is in contact with the fabric4, or the implant may comprise a second surface region includingliquefiable material. Such an optional second surface region 1.5 issketched in FIG. 1. Depending on the porosity of the flexible planarstructure, liquefiable material may then also penetrate structures ofthe flexible planar structure and cause an anchoring of the implant alsoin the flexible planar structure, strengthening the fixation of theflexible planar structure to the implant.

In this and in all subsequently described embodiments, the implant may,instead of being provided with a surface region of liquefiable materialin its initial state, also comprise liquefiable material that gets tothe surface, for example, from an inside of the implant.

For reliably fixing the flexible planar structure within the body, it isadvantageous to have a fixation that is effective on a large area. Onepossibility of achieving this is illustrated in FIG. 2. A plurality ofimplants 1 is used for fixing a section of a fabric 4 to a bone tissue2. The implants during implantation directly penetrate the fabric 4. Theimplants may be of the kind described in FIG. 1. The embodiment shown inFIG. 2 features the following advantages:

The strength of the anchoring in the bone tissue and of the attachmentof the flexible planar structure to the bone tissue is high;

The anchorage is relatively easy to be made;

The tension of the fabric 4 can be controlled;

The implantation brings about a low trauma only, especially if theimplants are chosen to be comparably small;

The position of the fabric can be chosen freely.

FIG. 3 illustrates an embodiment of the invention where the implant 11functions as a kind of rivet-like anchor for the fabric. Theillustration on the left-hand side shows an implant inserted in bonetissue. In this and in all following figures the micro-interlocking ofthe liquefiable material with the bone tissue is not especiallyemphasized. The proximal side of the implant 11 comprises an elementthat may penetrate the fabric 4 when the implant is already inserted. Inthe shown embodiment, the element is a needle-like protrusion 11.1capable of piercing the fabric when the fabric is placed on the bonetissue with the implant. The implant 11 further comprises a shoulder11.2 to which ultrasonic vibrations may be applied when the implant isinserted in the bone tissue cavity. To this end, a sonotrode of a toolby which the implant is inserted has to be specifically shaped.

After the implant is inserted, as illustrated, for two alternatives, inthe middle and on the right-hand side of FIG. 3, the element is deformedin a rivet-like manner so that the fabric may not be removed afterdeformation. For example, the protrusion 11.1 (or other element) may bedeformed by ultrasonic vibrations impinging on it or possibly by simplyapplying a force on it with or without additional heating.

Therefore, in accordance with the embodiment of FIG. 3, the mechanicalvibrations during implantation impinge on a first surface portion (beingthe shoulder in the illustrated embodiment) in order to couple thevibrations into the implant and to enable liquefiable material to meltand to interpenetrate structures of the bone material. Thereafter, afteradding the flexible planar structure, a second surface portion of theimplant is impinged with energy so as to deform the implant in theregion of the second surface portion and to affix the flexible planarstructure and the implant to each other. This energy may again beapplied in the form of mechanical vibrations, or it may be applied inthe form of heat, for example. The impinging of the second surfaceportion with energy may lead to an interpenetration of the implant andthe flexible planar structure, for example, by having implant materialmelt and fill pores in the flexible planar structure if the flexibleplanar structure is a fabric.

The introduction of the implant and the deformation of the protrusion11.1 may be combined in one step if the penetration of the fabric 4 bythe protrusion is done before inserting the implant into the bonetissue. Also, this embodiment features the advantage that the strengthof the anchoring in the bone tissue and of the attachment of theflexible planar structure to the bone tissue is height. Also, therivet-like implant is relatively easy to insert.

The embodiments illustrated in FIGS. 4 a and 4 b, and in FIGS. 5 a and 5b, respectively, both rely on a common principle. A clamp element 21.1,25 comprises two jaws which are swivellable relative to each otherbetween an open state (illustrated in FIGS. 4 a and 5 a) and a closedstate (illustrated in FIGS. 4 b and 5 b) of the clamp element. At leastone of the jaws comprises a plurality of needle-like micro-pins 21.2,25.1 capable of piercing the flexible planar structure when it isinserted between the jaws. The clamp element 21.1 shown in FIGS. 4 a and4 b is a part of an implant 21 to be implanted in the above-describedmanner, whereas the clamp element 25 is separate from the at least oneimplant 26 by which it can be fastened to the bone tissue. The clampelements may be fixed in their closed position by an additional implant22, 26 as illustrated or by other means. Preferably, in any case,ultrasonic vibrations are used to close the clamp element.

The embodiment of FIGS. 4 a through 5 b feature the advantage that thefastening may relatively easily be revised.

The implants in accordance with the embodiments of FIGS. 6 a through 8 ball include an area contact portion which is a portion that isessentially orthogonal to the implant axis. FIGS. 6 a and 8 a eachillustrate a multi-implant element 31, 51, and FIG. 7 a illustrates animplant 41. FIGS. 6 b, 7 b, and 8 b show the multi-implant element 31,51 or implant 41, respectively introduced into the bone tissue throughthe fabric 4 to be fastened thereto.

The multi-implant element 31, 51 of FIGS. 6 a and 8 a includes aplurality of implants 31.1, 51.1 which may comprise a tip-shaped distalend so that they can pierce the fabric 4 when being introduced in thebone cavity. They further include at least one bridge 31.2, 51.2 servingas the area contact portion. The area contact portion of the implant 41of FIG. 7 a is formed by a bent-off tapered bow (claw) 41.2 that isespecially suited for being placed along an edge of the fabric 4. Thebridge and the claw serve for stapling the fabric down and additionallymay connect the implants. The multi-implant element or implant may bepre-fabricated to comprise the bridge or claw. As an alternative, forspecial applications the bridge or claw may also be added in situ.

An implant or multi-implant element according to any one of the aboveembodiments may, in addition, comprise further elements for carrying outfurther functions and not being shown in the above figures. Such furtherelements may include guidance and/or holding mechanisms for sutures(threads or wires) and/or straps etc., such as an eyelet etc.

The fabric 4 of FIG. 9 is fastened to the bone tissue in accordance withany embodiment of the invention, for example, any one of the embodimentspreviously described or illustrated in the following. In the illustratedversion, the fabric 4 is attached by means of implants 1 of the kindillustrated in FIGS. 1 and 2. The fabric 4 serves as a pinned suturingfabric that may, for example, be used for suturing a ligament 64 ortendon to the bone. In this way it serves as universal base to suturedown the ligament or tendon. The fabric 4 can further support theligament or tendon integration by acting as scaffold and as a releasesystem for growth factors. In the figure, a suture (thread or wire) 61with a needle 62 is also shown.

For the embodiment of FIG. 9, the fabric may be especially coarselymeshed.

The embodiment features substantial advantages. Next to providing astrong and reliable connection between the bone and the ligament ortendon, the fabric is also easy to affix. It allows an excellent controlof the tension of the ligament or tendon. The implantation brings abouta low trauma only, especially if the implants are chosen to becomparably small. Both, the fabric relative to the bone tissue and theligament or tendon relative to the fabric can be flexibly positioned,and the position of the ligament or tendon can easily be revised.

Referring to FIGS. 10 through 15, examples of applications of theinvention are illustrated. In all figures, the implants and theirconnection to the flexible planar structure are illustrated only veryschematically. It shall be understood that the above teaching referringto embodiments of the method, implant, and kit of parts applies to theillustrated applications and to further applications mentioned above.

FIG. 10 illustrates an application of the previously described methodfor fixing a flexible planar structure to bone tissue. A bone graft 103is placed in a cavity formed by a recess in a bone tissue 102 (forexample after a tumor operation) and is held in place in the cavity bymeans of a mesh 4. The mesh is attached to the bone tissue 102and—optionally—also to the bone graft 103 by means of the methodaccording to the invention.

FIG. 11, illustrates yet another application of the previously describedmethod for fixing a flexible planar structure to bone tissue. Twovertebrae 112 on the left-hand side are stabilized with respect to eachother by means of a flexible planar structure 4 which is fixed to thetwo vertebrae by means of the method according to the invention. On theright-hand-side of the figure, the vertebrae are stabilized by means ofbone fragments 113 which are fixed apically and caudally by a flexibleplanar structure 4. In the illustrated embodiment, the flexible planarstructure is fastened to the vertebral bone tissue by implants 1 of thekind illustrated in FIG. 1.

FIG. 12 shows a flexible planar structure serving as a ligament implant,namely as a substitute for the tibial collateral knee ligamentconnecting the femur 131 to the tibia 132.

FIG. 13 concerns hernia repair and/or prevention. The flexible planarstructure 4 in FIG. 13 is attached to two vertebral bodies 141 forpreventing the (natural or artificial) intervertebral disc 142 betweenthe vertebral bodies from sliding out in the direction of the arrow 143.

The flexible planar structure 4 of FIG. 14 serves as spacer betweenelements of an osteoarthritic joint. The figures very schematicallyshows portions of the metacarpal 151 and the proximal phalanx 152 of ahuman thumb, between which the flexible planar structure 4—being afabric—acts as spacer.

FIG. 15 shows a bone 161 with a cavity 161.1 that has been caused bybone harvesting. The flexible planar structure 4 serves for covering thecavity 161.1 during the re-growth process of the bone and for therebypreventing an organ 162 of soft tissue from being pressed into thecavity.

FIG. 16 shows a flowchart of an embodiment of the method according tothe invention.

FIG. 17, shows an embodiment of the invention where the implant is notpre-fabricated but formed in situ. To this end, a thermoplastic polymerfilm being the flexible planar structure 4 is placed on top of the bonetissue. Thereafter, a sonotrode is pushed through the polymer film andinto the bone material while being subject to ultrasonic vibration. Bythis, a structure which protrudes into the bone tissue 2 is generated,said structure constituting the implant 121. The implant's 121 surfaceinterpenetrates the porous bone tissue, by which effect the implant isanchored in the bone tissue.

Whereas in FIG. 17, a pin-shaped, needle-type sonotrode is shown, thesonotrode could equally well be a punch type sonotrode or have any othersuitable shape.

FIG. 18, finally, illustrates an embodiment where the implant 1 and theflexible planar structure are intimately connected by means of a forcepulling the implant towards the proximal side.

In the Figure, the implant is of a special construction including aplurality of components. 1.11, 1.12, 1.13. The components in theillustrated example are approximately symmetrical with regard to anyrotation around its axis, which here serves as a compression axis. Thefirst component 1.11 (seen from the distal side) has essentially theshape of a truncated cone, here with a continuous axial drilling(clearance). The second component 1.12 has essentially the shape of ahat, here with a central axial drilling. The third component 1.13 hashere the shape of a cylinder with a conical clearance coaxial to thecylinder axis and a central drilling also coaxial to the cylinder axis.The central drillings of the first, second and third component arecoaxial to each other and of approximately the same diameter. Ifapplicable, deviating from the rotational symmetry, at least the centralcomponent 1.12, e.g. also the third component 1.13, possibly also thefirst component 1.11, are advantageously slit, which is not shown in thefigure. Because of the slit(s) the relevant components are easilyexpandable and the implant as a whole can be compressed along thecompression axis by a relatively moderate compression force. As thecompression force 174 is introduced, the components 1.11, 1.12, 1.13 aremoved along surfaces extending obliquely (i.e. at an angle, neitherparallel nor perpendicular) to the compression force. This constructionaims at causing peripheral surfaces of the components 1.11, 1.12, 1.13to excerpt radial forces onto a wall of an opening in the hard tissue171 when compressed along the compression axis. By this, the anchoringin of the implant in these circumferential walls instead of the distalbase surface of the hard tissue opening is achieved. This effect isfurther described in the provisional U.S. patent application 60/826,300,the teaching of which is incorporated herein by reference.

The vibrations and the force acting upon the implant are coupled intothe implant by a tool 172, which is exposed to a pulling force. The tool172 comprises a shaft 172.4 and a base plate 172.5. The shaft and/or thebase plate can therein make up a substantial part of the cross-sectionof the whole configuration and form the load-bearing part, e.g.consisting of titanium, of the implant after implantation, i.e. afterimplantation, the tool does not have to be removable.

During the implantation procedure, a pulling force and mechanicalvibrations are simultaneously coupled into the tool 3. This couples themechanical vibrations and the pulling force—as compression force—intothe implant. A counter pressure element 176 prevents the implant frombeing simply moved out of the opening. In the illustrated example, thecounter pressure element 176 is designed as a plate.

The flexible planar structure 4 comprises an opening through which theshaft 172.4 protrudes. The diameter of the opening in the flexibleplanar structure is smaller than the diameter of the proximalthermoplastic implant surface, so that the flexible planar structure isin contact with the proximal thermoplastic implant surface. When themechanical vibrations and the pulling force are applied between the tooland the counter element, the thermoplastic material of the implant meltsin vicinity of the flexible planar structure. As a consequence:

if the flexible planar structure comprises pores, for example because ofbeing a fabric, the thermoplastic material interpenetrates the pores andthereby, after re-solidifying, forms an intimate connection with theflexible planar structure.

if the flexible planar structure is thermoplastic and liquefiable underthe conditions present during implantation, a weld connection is formedbetween the flexible planar structure and the implant.

If the flexible planar structure is neither porous northermoplastic—which is less preferred—, nevertheless a connection may beformed by the re-solidified thermoplastic material sticking to thesurface of the flexible planar structure.

Following the implantation procedure the tool 3 can be applied invarious ways:

The tool can remain in the place of the implantation. This embodiment isparticularly advantageous when the tool is designed to simultaneouslyperform another function. Thus the tool can serve e.g. as an anchoringelement for the attachment of a thread, a tape, a sinew, another bone,an endoprosthesis or any other element. It can also perform otherfunctions known to be performable by implanted objects.

Providing the opening in the bone tissue is continuous, the tool can beseparated from the vibratory device and removed from the distal side.

The tool can be removed from the proximal side. In this case the tooland the continuous opening in the implant, through which the shaft 3.4is conducted during the implantation procedure, must be of a specialshape not symmetrical at any angle with regard to the rotations, whichis discussed in more detail below.

Embodiments of FIGS. 3, 4 a/4 b, 5 a/5 b, and 9 may also be implementedif the implant is not fixed by means of liquefying thermoplastic orotherwise liquefiable material, but is fixed conventionally or inanother alternative manner, for example, as a screw or a conventionalagraffe or the like. The embodiments of 6 a/6 b, 7 a/7 b, 8 a/ab mayalso be implemented if the implant is not fixed by means of liquefyingthermoplastic or otherwise liquefiable material, but is fixedconventionally or in another alternative manner and by means ofretention structures such as shingles, riffles etc.

Whereas in the above-described embodiments, the flexible planarstructure is placed on top of the bone tissue, this need not be thecase. Rather, the flexible planar structure could, by means of animplant of appropriate length, be anchored in bone tissue through softtissue like ligament, capsula, cartilage or other soft tissue.Thereafter, the flexible planar structure does not adhere to the bonetissue but to the soft tissue between the flexible planar structure andthe bone tissue.

Various other embodiments may be envisaged without departing from thescope and spirit of the invention.

What is claimed is:
 1. A surgical method for fastening a flexible planarstructure to hard tissue or hard tissue substitute material with the aidof an implant, the method comprising the steps of: providing the implantwhich comprises a distal end portion and a proximal end portion and,arranged on the proximal end portion, a solid first material havingthermoplastic properties and being liquefiable by application of energy,providing the flexible planar structure which comprises a first and anopposite second principal surface, and which, at least in a connectionarea, comprises at least one of pores and spaces and a solid secondmaterial having thermoplastic properties and being liquefiable byapplication of energy, establishing a first connection between theconnection area of the flexible planar structure and the proximal endportion of the implant, and establishing a second connection between thedistal end portion of the implant and the hard tissue or hard tissuesubstitute material, wherein, in the step of establishing the firstconnection, the proximal end portion of the implant is pressed againstthe connection area of the flexible planar structure and the firstmaterial is liquefied at least partly by application of energy to theproximal end portion of the implant for a time sufficient forestablishing at least one of an interpenetration of the pores or spacesby the liquefied first material and a weld between the first and secondmaterial.
 2. The method according to claim 1, wherein the flexibleplanar structure is an artificial structure and is a web, a membrane, afoil, a textile or a fibrous structure.
 3. The method according to claim2, wherein the textile or fibrous structure is woven, non-woven,knitted, braided or embroidered.
 4. The method according to claim 1wherein the step of establishing the first connection is carried outsubstantially simultaneously with or after the step of establishing thesecond connection.
 5. The method according to claim 1, wherein, in thestep of establishing the first connection, ultrasonic vibration energyis applied to the proximal end portion of the implant.
 6. The methodaccording to claim 1, and further comprising a step of positioning theflexible planar structure with the first principal surface against anexposed surface of the hard tissue or hard tissue substitute materialand the second principal surface comprising at least part of theconnection area facing away from the exposed surface.
 7. The methodaccording to claim 6, wherein the step of positioning the flexibleplanar structure is carried out before the step of establishing thefirst connection.
 8. The method according to claim 7, wherein theproximal end portion of the implant comprises a protrusion whichprotrudes on at least one side laterally over the distal end portion ofthe implant, and wherein, in the step of establishing the firstconnection, the protrusion is positioned and pressed against the secondprincipal surface of the flexible planar structure.
 9. The methodaccording to claim 8, wherein at least two implants are provided andwherein the protrusions of the at least two implants are joined togetherto form a bridge between the at least two implants.
 10. The methodaccording to claim 8, wherein the step of establishing the firstconnection further comprises producing the protrusion by deforming theproximal end portion of the implant.
 11. The method according to claim10, wherein, for deforming the proximal end portion of the implant,ultrasonic vibration and a pressing force are applied to the proximalend portion of the implant.
 12. The method according to claim 6, whereinthe step of establishing the second connection comprises providing anopening in the hard tissue or hard tissue substitute material throughthe exposed surface in a location, which is at least one of underneathor beside the positioned flexible planar structure, and positioning thedistal end portion of the implant in the opening.
 13. The methodaccording to claim 12, wherein the opening is provided by forcing thedistal end portion of the implant into the hard tissue or tissuesubstitute material.
 14. The method according to claim 12, wherein thestep of establishing the first connection further comprises providing athrough opening through the flexible planar structure and positioningthe implant in the through opening with the proximal end portionextending beyond the second principal surface of the flexible planarstructure.
 15. The method according to claim 14, wherein the throughopening is produced by forcing the distal end portion or the proximalend portion of the implant through the flexible planar structure. 16.The method according to claim 12, wherein the hard tissue or hard tissuesubstitute material comprises, inside the opening in the hard tissue orhard tissue substitute material, at least one of unevenness, pores andartificially made retention structures, wherein the distal end portionof the implant comprises a third material having thermoplasticproperties and being liquefiable by application of energy, and whereinthe step of establishing the second connection comprises liquefying atleast part of the third material by application of energy to theproximal end portion of the implant and by letting the liquefiedmaterial to penetrate into the unevenness, the pores or the artificiallymade retention structures and to solidify therein.
 17. The methodaccording to claim 16, wherein the energy applied to the proximal endportion of the implant is ultrasonic vibration energy.
 18. The methodaccording to claim 16, wherein the first and third material constituteat least part of the implant surface.
 19. The method according to claim16, wherein the first and third material are based on a samethermoplastic polymer.
 20. The method according to claim 19, wherein thewhole implant is based on said same thermoplastic material.
 21. Themethod according to claim 16, wherein the implant comprises a hollowspace which is accessible from the proximal end portion of the implant,is at least partially filled with the third material, and is connectedto a surface of the distal end portion of the implant by a plurality ofchannels, and wherein, in the step of establishing the secondconnection, the energy for liquefying the third material is applied to aproximal face of the third material and the liquefied third material isforced through the channels.
 22. The method according to claim 21,wherein the first material is the same as the third material and is alsoarranged in the hollow space, wherein the hollow space is connected by aplurality of further channels to a surface of the proximal end portionor the implant, and wherein, in the step of establishing the firstconnection, the energy for liquefying the first material is applied to aproximal face of the first material and the first material is forcedthrough the further channels.
 23. The method according to claim 22,wherein the first and the third material are the same material.
 24. Akit of parts for performing a surgical method for fastening a flexibleplanar structure to hard tissue or hard tissue substitute material withthe aid of an implant, the kit comprising: the implant which comprises adistal end portion equipped for being connected to the hard tissue orhard tissue substitute material and a proximal end portion and, arrangedon the proximal end portion, a solid first material having thermoplasticproperties and being liquefiable by application of energy, and theflexible planar structure which comprises, at least in a connectionarea, at least one of pores and spaces and a solid second materialhaving thermoplastic properties and being liquefiable by application ofenergy, wherein, the implant and the flexible planar structure areadapted to each other for enabling establishment of a connection betweenthe proximal end portion of the implant and the connection area of theflexible planar structure by liquefaction of at least part of the firstmaterial to achieve at least one of an interpenetration of the pores orspaces by the liquefied first material and a weld between the first andsecond material.
 25. The kit of parts according to claim 24, wherein theflexible planar structure is an artificial structure and is a web, amembrane, a foil, a textile or a fibrous structure.
 26. The kit of partsaccording to claim 25, wherein the textile or fibrous structure iswoven, non-woven, knitted, braided or embroidered.
 27. The kit of partsaccording to claim 24, wherein the implant is a pin, or a pin with aproximal end portion constituted by a head, a claw or a bridge by whichthe implant is joined to at least one further implant.